THE economic downturn could be longer and deeper if Government plans to restrict immigration are implemented, a think tank said today.

THE economic downturn could be longer and deeper if Government plans to restrict immigration are implemented, a think tank said today.

The left-leaning Institute for Public Policy Research (IPPR) said the number of people coming to Britain for work would reduce "naturally" as the economy slowed.

Placing restrictions on migrants who plug skills gaps or take jobs which Britons will not do will damage the economy, researchers said.

The Immigration and Citizenship Bill, which will be published tomorrow, will end the automatic right to stay after five years andintroduce "earned citizenship".

Migrants who can demonstrate a knowledge of English and life in the UK and who carry out voluntary work will have their timetable for citizenship speeded up.

The Bill will also place restrictions on migrants' access to benefits and housing.

Tim Finch, head of the IPPR's migration team, said: "Migrants become easy targets at times of economic difficulty but introducing yet more tough measures to exclude people could damage our prospects for economic recovery.

"As it stands, the Borders, Immigration and Citizenship Bill could deter migrants who are in high demand and who are essential for our economy "Not all migrants will want to settle in the UK, but some will and so it's important that the over-complicated process of "earned citizenship" is made clear and fair."

He said it could be unfair to deny benefits to migrants who are working and paying taxes.